Sample records for energiaskor totalhalter lakbarhet
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Energy Technology Data Exchange (ETDEWEB)
Baeckstroem, Mattias [Oerebro Univ. (Sweden)
2006-01-15
In the current project total concentrations for antimony in 31 energy ashes have been compiled. The average concentration of antimony in boiler fly ash and grate boiler fly ash is 192 and 1,140 mg/kg, respectively. The corresponding antimony concentrations for boiler ashes and grate bottom ashes are 86,5 and 61,8 mg/kg, respectively. Multivariate calculations clearly pointed out waste as the major source for antimony in ashes. The difference between total antimony concentration in fly ash and bottom ash is greatest for grate boilers, in average 18 times higher in the fly ash. The difference for CFB/BFB-boilers is only slightly more than 2. However, based on amount, 75% of the total antimony inventory is recovered in the fly ashes for both CFB/BFB and grate boilers. Eleven (eight of which were bottom ashes) out of the 31 samples exceeded the guidelines for inert waste. It is clear that the higher ionic strength in the solutions from the fly ashes contribute to decrease the solubility for critical minerals retaining antimony. In addition, the fly ashes have considerably larger effective surface able to sorb trace elements. A clear and positive covariance was discovered between aluminium and antimony. Furthermore, it was noted that antimony showed no typical anionic behaviour despite the fact that it according to the geochemical calculations should be present as SbO{sub 3}{sup -}. At L/S 10, a maximum of 1% of the total antimony concentration is leached. This should be compared to chloride that had 94% of the total concentration leached at L/S 10. There was no correlation between the leached antimony concentrations and the total antimony concentrations. The sequential extractions also suggest a low leachability for antimony from the ashes. In average only 9,6% is released at pH 7, 7,3% at pH 5, 3,6% during reducing conditions and 3,2% during oxidising conditions. In total, only 24% of the total antimony concentrations is released during the four extraction steps. The remaining 76% is probably to be found in the silicate matrix. Through multivariate calculations (PCA and MLR) and geochemical calculations (PHREEQC) aluminium and sulphate have been identified as being important for antimony leaching from the ashes. It is thus likely that ettringite governs antimony leachability at alkaline pH. When ettringite is solubilized the leachability of antimony will be dependent on the presence of effective sorbents. To decrease the leachability of antimony from the ashes addition of sulphate solution to the ashes is suggested, to increase the stability of ettringite at alkaline pH. Below the pH-range where ettringite is stable addition of manganese solution would give a new effective sorbent for antimony in solution. It was also noted that all fly ashes with addition of activated carbon did not exceed any guide lines for antimony leaching.
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Energy Technology Data Exchange (ETDEWEB)
Svensson, Malin; Herrmann, Inga; Ecke, Holger [Luleaa Univ. of Technology (Sweden); Sjoeblom, Rolf [TEKEDO AB, Nykoeping (Sweden)
2005-05-01
In the project SMAK, the selective mobilization of critical elements in ashes was studied. Non-hazardous bottom ash from Daava kraftvaermeverk, Umeaa, and hazardous fly ash from Hoegdalenverket, Stockholm, line P6 were investigated. Sb, Mo, Cu, Cr and Cl{sup -} were identified as critical elements in the bottom ash since these elements exceeded the limit values for acceptance on landfills as inert waste according to the Council decision on acceptance criteria at landfills. Critical elements in the fly ash were Cr, Se, Pb and Cl{sup -}, these elements exceeded the limit values for acceptance on landfills as non-hazardous waste. The mobilization of the critical elements was studied in experiments performed according to a reduced 2{sup 6-1} factorial design with three centerpoints. Factors in the experiments were ultrasonic pre-treatment, pre-treatment with carbonation, L/S-ratio, pH, time and temperature. Empirical models of the mobilization were used to identify the optimal factor setting ensuring sufficient mobilization of critical elements, i.e. to achieve a solid residue meeting non-hazardous and inert landfill criteria for fly ash and bottom ash, respectively. No ultrasonic treatment, pre-treatment with carbonation, L/Sratio 5, pH 12, time 2h and temperature at 20 deg C were identified as optimal factor setting for the bottom ash. For the fly ash, no ultrasonic treatment, no pre-treatment with carbonation, L/S-ratio 5, pH 7, time 2h and temperature at 20 deg C were identified as optimal factor setting. The treatment with optimal factor settings did not change the classification according to the Council decision on acceptance criteria at landfills of neither ash. For the bottom ash, Sb, Mo and Cr exceeded the limit values for landfilling as inert waste according to the Council decision on acceptance criteria at landfills. Only Cr exceeded the limit value for landfilling the fly ash as non-hazardous waste. According to the Waste Decree (Avfallsfoerordningen) both treated ashes were classified as non-hazardous waste. No negative effects on the geotechnical usage could be found in the classification according to the Waste Decree. A comparison to the general guidance values for contaminated soil according to the Swedish Environmental Protection Agency showed that both of the treated ashes did not meet the limit value for less sensitive land use. Since the ash properties deviated from the reference soil in the general guidance values for contaminated soil according to the Swedish Environmental Protection Agency, a case in point was calculated. The results showed that both ashes met the recommended limit values for less sensitive land use, with and without groundwater usage for households. The main reason for this is that substances which may influence health and environment are maintained much more strongly in the ash as compared to the soil that The Swedish Environmental Protection Agency used in its calculations for the reference values for contaminated soil. This implies that the content of such substances in the groundwater will be low and thereby also any possible effects arising in the different scenarios. (In certain cases it is possible that the ash will behave as a sink for hazardous substances even in cases where the content in the ash will exceed that of the surrounding soil.)
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Energy Technology Data Exchange (ETDEWEB)
Loevgren, Linnea; Wik, Ola
2009-10-15
The new chemical regulation, REACH (1997/2006/EC), Registration, Evaluation, Authorization and restriction of Chemicals, took effect the 1st of June 2007. The background to this report was the introduction of REACH and the difficulties to understand the implications for ash. The most important consequence of REACH is that all chemical substances that are manufactured, handled and used above one tonne per annum per legal entity shall be registered according to this regulation. The registration includes specifying the chemical, physical, toxicity and ecotoxicity properties of the substance and risk assessing the identified areas of use. The report describes the use of ash in connection to the waste legislation and its planned end-of-waste-criteria, the chemical legislation and the Construction Products Directive. The target audience of this report is companies producing ashes and having a use or seeing a use for its ash. The report describes how to make a REACH registration of ash independent if a company did or did not pre-register ash during 2008. It describes how to change from one ash registration into another if the pre-registration was done for one type of ash but the company changes opinion during the sameness check, i.e. changing SIEF (Appendix A). Taking part in REACH registration projects during 2009-2010 can be advantageous since knowledge and financing are shared. Ash can be REACH registered also in the future but it is important to know that the registration have to be done prior the production and marketing starts. If ash is consider to be a waste the handling is covered by the community and national waste legislation. In Sweden ashes are by and large being regarded as waste, and recycling is risk assessed and permits are given case by case. End-of-waste criteria for different waste material are being elaborated within the EU. Such criteria will among other details cover chemical safety. When a material fulfils the end-of-waste criteria such material will have the possibility to leave the waste legislation and be covered by the chemical legislation in becoming a product or an article. It is not know in detail how far the chemical legislation will reach for material having end-of-waste criteria. Currently, end-of-waste criteria have not yet been initiated for ashes. The Swedish Environmental Protection Agency (Naturvaardsverket) is currently elaborating end-of-waste criteria for the use of material in construction works. Recovering waste is according to REACH identical with manufacturing. A chemical substance, preparation/mixture or article manufactured from waste, i.e. via a recovering operation will have to follow chemical legislation. The enterprise responsible for the recovering operation is the legal entity responsible to follow REACH for the manufactured material. One example of recovering ash into a chemical substance is the manufacturing of cement when ash is the raw material. It is the responsibility of the cement plant to have its substance or product REACH-registered before manufactured and provided to a third party. The waste legislation, instead of the chemical legislation, applies when the waste recovering operation does not results in manufacturing of a substance, preparation or article provided to a third party and the waste has a use at the end of its life cycle. This is identified as late recovery. The waste legislation applies during the life cycle of the waste in such cases. Examples in Sweden are ashes used in landfill sealing and covering layers and in roads or soil stabilization. Use of ashes in constructions is covered by the Constructions Product Directive (2008/98/EC), CPD, irrespective if it is identified as a waste or a chemical product. The CPD harmonizes only testing and CE-marking of construction products. Chemical safety requirements originate from national legislation which in many cases is based on chemical regulation. Standardized testing methods to measure emitted hazardous substances from construction products were initiated in 2006 on the EU level. The proposed method s are similar to leaching methods used today in characterization of waste properties for landfill. The report describes pros and cons with REACH registration of ashes. It is believed that uses of ashes will more easily be available if the ashes are registered according to REACH. The reason is that a REACH registration generates extensive information about properties and emissions during uses and that safety instructions will be available to guarantee that emissions will not be higher than what man and nature can sustain. The fee for a joint submission of a REACH registration is 23,250 Euro per legal entity if the company put more than 1,000 tonnes of the dry substance on the market per year.
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Energy Technology Data Exchange (ETDEWEB)
Nordstroem, Erik; Thorsell, Per-Erik
2003-10-01
A compilation of regulations and best practice from different techniques to utilize ashes in concrete related applications is presented in this report. The term 'concrete related' applications also include geotechnical applications where cement is used as a binder. It can be seen that fully developed regulations is only available for concrete used as a structural building material. In other applications the formulations give an opportunity to use alternative materials as long as similar properties are achieved. In some applications not even this type of regulations are available but the alternatives are judged from case to case. The purpose with this work was to high-light acceptable variations for the parameters where limitations on constituent materials are formulated. During the work it has become clear that the task is not possible to solve since this kind of values seldom are available. A discussion about the economical potential for different applications is presented in the end of the report. In summary, the concrete applications do not allow the major part of the ashes to be utilized and the demands on the ashes are high. But it can also be stated that the high costs for cement give a big incitement for change of binder in concrete to e.g. flyash. In the geotechnical applications there is also a big potential both regarding technical and economical aspects, but the possible effects on soil and ground water will give rise to more rigorous considerations by the environmental authorities. Finally, the mining applications can give a large amount of ashes to be utilized in a limited region, and the transport cost can be problematic for the ash producers. The conclusions from the present work are that there exist several possible concrete applications also for other ashes than pure coal ashes. Type of ash, available amounts, storage facilities, local market, stability in fuel-mix, personal interests are important parameters influencing the possibilities for utilization. This work has identified a potential for utilization of ashes as: filler material in concrete with crushed aggregates and in self compacting concrete; in mining applications; road building material with improved frost properties; in ground stabilisation with lime/cement columns and in cement stabilised gravel; in injection grouts for stabilisation of soil and depots. A final aspect on the possibilities to utilize ashes is the general acceptance level which influence the potential. Many concrete manufacturers are skeptical against use of flyashes in concrete. A change can be seen nowadays with an increased interest for ashes and residues in concrete. Higher level of environmental awareness further strengthen this change. By no means the safety and durability should be risked but where use of ashes is possible money can be saved and also the CO{sub 2}-emissions are lowered (very high during cement production)
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Energy Technology Data Exchange (ETDEWEB)
Sundblom, Hillevi
2004-01-01
The Swedish concrete producers have decided to work towards a common goal to limit the production of concrete with naturally rounded aggregate. A consequence is when use of a substitute, crushed aggregate, the demand of filler material increases. During the last years ashes form the CFB boiler in Perstorp has been utilised as a filler material, with success, in concrete production at Sydsten, Malmoe, Sweden. To examine the potential of using Swedish fly ashes as a filler material in concrete production, have different Swedish fly ashes above been studied to see if they fit the requirements for a filler material. The fly ashes studied in the project can be divided into four different groups, considering fuel mix and boiler type; 1. Bio and sludge fired CFB/BFB boiler from the paper industry, 2. Bio and peat fired CFB/BFB boiler, 3. Pulverized peat/coal firing furnace, 4.Bio and peat fired grate-fired boiler. From Sydsten experiences of using Swedish fly ashes two demands have emerged concerning the chemical composition of the ashes. The total amount of chloride in the concrete should not be higher than 0,1% and the LOI, (Loss Of Ignition) must be less than 10 %. The different ash analyses showed that the fluidised bed boilers and pulverized firing furnaces, in this study, passed all the chemical requirements but the grate fire boilers had difficulties to fulfil the requirement of LOI. The ashes chosen to be studied in further rheological investigations in different fresh concrete mixtures were, Category 1 (Hallstavik's and Hyltebruk's papermill), Category 2 (Vaesteraas Vaermeverk och Vaertaverket) and from Category 3 (Vattenfall Vaerme Uppsala). The results presented an increased water consumption of ashes from paper mills comparing with the other ashes, a probable reason could be the shape of the ash grains. The experiments also showed that all ashes contributed to the final strength of the hardened concrete, the paper mill ashes also contributed to the initial strength development. During mixture of the fresh concrete with an ash quantity of 60 kg/m{sup 3}, it different degrees of loss of consistency was observed during the first hour after mixing. When decreasing the amount of ash to 30 kg/km{sup 3}, it was only the paper mill ashes that could not maintain the consistency during the first hour. The mechanisms that are dominating in the interaction between ash and cement during the hardening of the fresh concrete are complex. The reasons why certain ashes create a greater loss of consistency than others are not fully understood. It is necessary to continue research in this issue for simplifying the choices when using ashes in different concrete application. This project resulted in full-scale demonstration. Sydsten in Malmoe delivered concrete with ash from the pulverized peat-firing furnace in Uppsala as a filler material to a concrete casting in Lund. The concreting was very successful. The concrete did not loose the consistency as noted in the laboratory experiments. The concrete also demonstrated an excellent workability. The overall conclusion is, some of the Swedish fly ashes are very suitable to use as a filler material in concrete. A full-scale demonstration and delivery to customer has already been made in south of Sweden (Sydsten). There is also potential to find methods to refine ashes, which today don't fulfil the requirements of consistency for example sieving, to reduce the quantity of LOI.